Hitherto, various methods of improving the image quality by enhancing a high frequency component, an edge component, or the like included in a luminance signal have been proposed in various video image apparatuses, such as display apparatuses. For example, a method of preventing an increase in noise and enhancing contrast is proposed in Japanese Unexamined Patent Application Publication No. 8-56316.
However, in these conventional techniques, there is a problem that the textures of details, such as grasses, flowers, the leaves of trees, and the surface of rocks, cannot be improved, although the vividness or the like of a display image can be increased.
In particular, when a video signal based on the SDTV (Standard Definition Television) system is format-converted to a video signal based on the HDTV (High Definition Television) system by performing scaling, the textures of these details, such as grasses, flowers, the leaves of trees, and the surface of rocks, are lost. There is a problem with the conventional techniques that the textures of these details cannot be improved.
Patent Citation 1: Japanese Unexamined Patent Application Publication No. 8-56316